A Neural Network Model for Stripe Formation in Primate Visual Cortex

Abstract

Spontaneous stripe formation occurs in many physical and biological systems1, for example, the formation of a striped pattern of ocular dominance columns on layer 4, area 17, of the visual cortex, observed in sections parallel to the surface of the cortex. The ocular dominance of a cortical neuron measures the difference in excitation of the neuron when each eye is stimulated separately. In primates it begins to develop shortly before birth. When both eyes experience a normal visual environment or are deprived of pattern vision (binocular deprivation) ocular dominance forms in parallel stripes2. This development is disturbed, however, when a single eye is deprived of pattern vision (monocular deprivation) in which case the stripes are spaced less regularly. They also thin, or ‘corrode’ into patterns with broken stripes3. These ocular dominance patterns are symptoms of changes in the strength of synaptic connections between cortical neurons and the neurons in the lateral geniculate from which they receive their input. A summary of the theory of synaptic development and an overview of experiments performed on animals with normal visual experience can be found in our previous work4,5.